Electric discharge apparatus



y 1946. R. M. SMITH ELECTRIC DISCHARGE APPARATUS Filed May 29, 1943 INVENTOR Fay/7. fmzzd. BY a f Fin-foamy Patented July 2, 1946 ELECTRIC mscnaaaa mana'rus R'oy M; Smith, Bethlehem, Pa assignor to The Bryant Electric Company, a corporation of Connecticut Bridgeport. Conn,

Application May 29, 1943, Serial No. 488,995

IZCIaims. (Ci. sis-e1) My invention relates generally to electric dis--- charge apparatus in the form of starting and operating control circuits and apparatus ior electric discharge devices uch as fluorescent lamps and, more particularly, to a two-lamp circuit and ballast for controlling the operation or a palr oi such devices from a common source of current where it is necessary or desirable that the control devices, such as the ballast and other control accesto bridge and floor lamps and other devices of a similar nature where it is desirable to conceal the control apparatus and mounting space therefor is at a minimum, it becomes highly desirable l to reduce the number of leads to a minimum numher and also reduce the number or control devices to only a single unit, it possible.

This. oi course, is exclusive or the two small starting switches or relays which are usually sories. be located remote from the lamp as, for 10 mounted on or adjacent to one of the lamp holdexample, in a bridge or floor lamp.

Heretoiore it has been the usual practice to operate two lamps from a single supply circuit by means'of a two-lamp control 'circuit'employing a single two-lamp ballastdevice and a separate ll the failure 01' some starter compensator device in the form 01' a small auxiliary reactor connected in the starting circuit circuitu 'Iheballast device of this circuit comprises a pair of reactors, one for each lamp, a capacitor for the leadinglamp and may also in-' clude a small "autotransiormer all enclosed in a are associated with each lamp.

In order to obtain this result. it is necessary to provide a control device or ballast which shall be reliable and not become useless on account of relatively unimportant andinexpensive part thereof requiring the replacement of the entire unit and also one which Mean 1 porates the tarting compensator in such manner that it will function. in the p oper w y d be so connected in the lamp circuit during the starting Period only.

The starting compensator referred to herein is in the form of a small auxiliary reactor comprising an iron core with an air gap and a winding metal housing or casing filled with a suitable inas thereon whlchis utilized to increase the preheatsulating compound. This device is commonly referred to as a two-lamp A starting w tch or relay-is provided ror'each the circuit and the circuit with respect to reducing the number of wiring 3 meme properly heated and the starting comiensator is connected in series circuit relation leads by simply omitting this element.

Accordingly it is an object or my invention to provide tor obtaining the .i'oregoing results by with the starting switch and the leading lamp providing a two-lamp control circuit for electric lrcuit only during the starting period when the In the usual application or the two-lamp cirit. the number oi' wlring leads required to conct the lamps mipment is of little or no consequence. This is the reason that. these devicesare usually Muted in a lighting iixture'where sumclent L00 is'avallable and in close proximity to each and. rendered inei'- 40 discharge lamps wherein the starting compensator device is incorporated into the ballast;

Another object oi" my invention is to provide a ballast device for use in two-lamp control circuits which embody as a part thereof a starting compensator together with asuitable switch device for rendering the compensator ineil'ective aiter'the lamphas startedi and during its normal operation.

45 A further objector my invention is to provide a two-lamp control circuit utilizing a minimum number of wiring leads between the lamps and the ballast devi Another object oi my invention is to provide a I a d th vst rt and control '60 two-lamp control circuit which i particularly suitable for use with bridge and iioor'lamps and the like. 4

Referring to the single figure oi the drawing which illustrates one embodiment oi'the invener. However. when these circuits are applied as tion in schematic form. the circuit there shown a manac comprises generally a pair of double-ended elecas the starting current of the lamp, it functions tric discharge lamps ill and II having electrodes not only to efiect closure of the switch contacts I2 and I3 and I4 and I5, respectively, which'are l2 and 43 but also to hold them closed 'during operated from a suitable current source, reprenormal operation of the leading lamp |0. sented by conductors l8 and I! by means of a Due to the fact that'the cutout switch 4| is of singleorcommon ballast device il'. the thermal, type, it has sufficient time delay The ballast It comprises a pair of main reactors characteristics to permit the capacitor 25 to func- IQ and 2| or their equivalent in the form of two tion during the starting period of the lamp and integral reactors, a transformer 22 and a capacithen cut it out of the lamp circuit after its functor 23 all enclosed in a. suitable housing or casing tioningis no longer required. It will be apparent 24 filled-with insulating compound in accordance that the same result is accomplished by means of with the usualwell-known practice. While the this arrangement as though the compensator 2'5 housing is not shown specifically, it is. to be 1111-, were disconnected by means of the opening operderstood that all 'of the elements within the ation of the starting switch 38. rectangle designated by the numeral 24 are a While 'the starting compensator 25 has been part of the unitary ballast. shown as a separate element of the ballast, it will In accordance with my invention, the ballast i8 be apparent that it also may be integral with one also includes a starting compensator 25 connected of the main reactors l9 and 2 I. By integral, it is in series-circuit relation with the reactor I! and meant that the-core structure of the compensator a condenser 23 in the circuit of the lamp III which may be an integral part of the core structure of is the leading lamp of the circuit through conone of the main reactors.

ductor 26 connected to one terminal 21 of elec- In view of the foregoing, it willbe apparent that trode ll. by incorporating the starting compensator in It is to be understood that in actual practice the ballast l8 and utilizing the cutout switch 4| to the terminals of the electrodes of the lamps are 25 control its efiectiveness, the two-lamp circuit has the contact pins which engage contact fingers in been simplified to the point where it is more suitthe lamp holders and that the circuit connections able for use with floor lamps and the like as only are made to the terminals of the lamp holders three main wire leads, namely 26, 28 and 33,

= instead of directly to the electrode terminalsas are required between the ballast I8 and the two shown. 30 lamps Ill and I l. Assuming that the compensa- The reactor 2 l is connected to the other lamp ll tor 25 was controlled in the usual manner by the through conductor 28 which is connected to one starting switch 38 and mounted in the base of the terminal 29 of electrode l5. Terminals 8| and floor lamp remote from the lamps in and H, it is the lamp discharge.

' switch or glow relay maybe usedfor this is, it will function during the startingperiod,

I in series with the starting switch 3| between the 22 of the other electrodes l2 and II, respectively. apparent that two additional wiring leads would are'connected through conductor 23 to the supbe required to make the connection.

ply conductor it. The other terminals I4 and The use of the cutout switch 4| makes it possi- 35 of lamp I0, and I6 and 31 of lamp II, are ble to locate the compensator 25 in the ballast connected together through suitable startin and utilize it as effectively as before. .All of the switches or relays 3! or", respectively, in awellv advantages of the prior two-lamp circuit are reknown manner to provide a preheating circuit 40 tained by the use of an additional inexpensive for the electrodes ofeach lamp during the start: cutout'switch and the field of application of the ing period and interrupt these circuits to initiate j" two-lamp circuit broadened. Thus in the case of floor and bridge lamps, the ballast in the form of a single piece of equipment may include all the necessary control devices and may be mounted or located in-the baseof the floor lamp without the m details of the starting switches a and have not been shown as any wellvknown thermal Since the starting compensator 2! is connected in series-circuitrelation with the main readm' The use of a thermal cutout switch in the ballast is not objectionable as the heating element use of extra leads as would otherwise be required. I

is, when the starting switch 28 islclosed in the so thereof is protected by the capacitor 23 in the p same mannerasthough it were connected directly event that the leading lamp burns out or'rails and commences to function as a rectifier. The

electrode terminals 14 and II. However, it will c'apacltor 23 prevents the flow of excess current also be apparent that the compensator'will be in isuch as would otherwise damage the heating elethe circuit of the lamp after the starting switch 55.;ni'ent of the control switch. Therefore; the incorll has-opened and the discharge-of the lamp poration of the compensator 25 into the ballast initiated. a a is not disadvantageous irom thi standpoint and. harder to provide for rendering the compcnsivtherefore, there is little likelihood of having the tor 2| ineffective during the normal operation of cutout switch fail and rendering the entire ballast the lamp, 9. cutout switch 4|. is .alsoincorporated an useless.

in the ballast for controlling the effectiveness of While only one specific embodiment of my in the starting compensator. This switch may take vention has been shown and described, it is ,to be any desiredform so long as it responds to the flow understood that other modifications may be made of starting current in. the leading lamp circuit withoutdeparting from-the principles of my inand in this instance is illustrated as a thermal Q5 vention. switch having normally open contact members 42 I claim as my invention:

and 4!, the movable-contact'member 42 being 1. An electric circuit for starting and. operating tuated by abimetal member thetemperah a plurality of electric discharge lamps having of which is controlledby a heating element ll electrodes from a single current source comprisconnected in the lamp circuit, as shown. :0 ing, circuit means for connecting said lamps in "The contact members 42 and 43 of this switch 7 parallel to the source, a single reactor connected are connected to shunt the start ng canpensator in series with one lamp, a plurality of reactors 28 when closed. Since the heating element 4' connected in series with another of the lamps, is in the circuit at all times, and thereby is suband current responsive switch means operable to jected to the normalvoperatins current as Well 15 shunt one of said series connected reactors from common current source, a reactor connected in series circuit relation with each lamp, an auxiliary reactor and a capacitor connected in the circuit of one lamp, and a thermal switch connected to be responsive to the starting current of the said one lamp circuit operable to shunt the auxiliary reactor from said circuit by a delayed action following the initial energization of the circuit to start the lamp.

8. In combination, a pair of electric-discharge lamps, circuit means comprising a ballast device for connecting said lamps in parallel circuit relation to a current source, said ballast device including a pair oi main reactors one for each lamp in each parallel circuit and an auxiliary reactor connected in series circuit relation with one of said main reactors, and current responsive means.

I nected in series circuit relation with one, lamp,

reactance means connected in series circuit relation with the other lamp, and switch means connected'to beresponsive to-the flow of starting current through said other lamp for shunting a portion or the reactance means in series circuit relation therewith after said lamp has started.

5. The combination with a source of electrical lih ' able I 6 x with each lamp to automatically control the heating current thereof, a first reactor connected in series circuitrelatlon with one lamp,'a second reactor and a capacitor connected in series sircuit relation with the other lamp lamp to draw a leading current from the source, a third reactor connected intermediate the second reactor and its associated capacitor to function as a starting compensator for the leading lamp, and a thermal switch responsive to the starting current in the leading lamp circuit operto shunt said third reactor following the initiation oi the discharge of said leading lamp.

8. The combination with a source of alternating current, of a pair of gaseous electric-discharge lamps having electrodes at each end thereof adapted to be supplied with preheating current, circuit means connecting one electrode terminal of each lamp to one sideoi the source and another electrode terminal of each lamp to the other side or the source, a starting switch connected between the other terminals oi the electrodes of each lamp for controlling the flow or preheating current through the electrodes and .the starting of the lamps, and a common ballast interposed in the circuit between the lamps and one side 01' the source, said ballast including reactor means in 'series with one lamp. reactor means and capacenergy, oi a, pair or electric discharge lamps, circuit means connecting said lamps to the source in parallel circuit relation, reactance means connected in series circuit relation with one lamp,

reactance means connected in series circuit relation with the other lamp, and switch means having normally-open contact elements connected in shunt relation with a means in series with said other lamp, and an operating element for said contact members connected to be responsiveto the flow of starting current in the circuit oi said other-lamp, whereby said switch means functions to render the said portion oi the reactance means .ineil'ective after the lamp has started. y

6. A starting and operating circuit for operating a pair of electric discharge lamps from a common source oi electrical energy comprising, circuit means for connecting said lamps to thecommon source in parallel circuit relation, and a single ballast deviceinterposed in the circuit means, said ballast including a main reactor connected tube in series with each lamp, an auxiliary reactor connected in series with one of the main reactors, and a current responsive shunting switch for said auxiliary reactor, said switch being connectedto respond to the starting current oiits associated lamp and operable to render the auxiliary reactor ineil' tive after the lamp has started. Y

7. The combination with a source of electrical energy, or a pair of electric discharge lamps connected in parallel circuit relation thereto. said devices having electrodes connected to be supplied with heating current, switch means cmnected portion of the reactance' to render itor means in serieswith the other lamp, whereby said lamps operate with lagging and leading currents respectively, and an auxiliary starting reactor incorporated in said ballast and connected in circuit relation associated reactor, corporated in said and a thermal switch also inballast and having a heating element connected to be responsive to the current flowing in the leading'lamp circuit operable to shunt said auxiliary starting reactor subsequent to the operation of the starting switches said auxiliary reactor ineffective during the normal operation of its associated lamp.

9. Inelectric discharge apparatus comprising, a pair 01 electric discharge devices connected to be operated in parallel from a source of alternating current supply and each having a pair of thermionic electrodes, a starting switch connecting each pair of electrodes in series to the source operable to control the heating of the electrodes and the starting of the devices, a first reactor connected in series with one of said devices, a

second reactor and a capacitor connected in series with the other of said devices, said reactors and capacitor constituting a ballast for operating both lamps together from a common current source, a starting reactor forming a part of the ballast and being connected in series withthe second reactor and capacitor, and switch means also forming a part of the ballast and operable to short circuit said starting reactor in predetermined amount of current therethrough during the starting period of its associated lamp, thereby to render said starting reactor ineffective during the normal operation oithe lamp.

19. A unitary ballast device for use in a twolamp control circuit for electric discharge lamps andthe like comprising, a pair of main reactors connected in disposed for connection. to a separate discharge lamp, an auxiliary reactor connected in series circuitrelation with one or said main reactors, andswitch means having contact members connected in shunt relation with the auxiliary reactor and an electroresponsive operating element connected to be energized in accordance with the current ilow through the auxiliary reactor. thereto cause said with the capacitor and its response to the flow of a parallel circuit relation and each a disposed for connection asbsaao by to provide for shunting the auxiliary reactor from its associated parallel circuit in response to predetermined current flow there'throush.

1-1. A unitary ballast device for use in a twoiamp control circuit for electric discharge lamps and the like comprising, a pair of main reactors connected in parallel circuit relation and each to a separate lamp, an auxiliary reactor connected in series circuit relation with one of said main reactors, and thermal switch means operable reactor from its associated parallel circuit by a delayed action in response to the flow or a predetermined amount of current therethrough.

12. A unitary ballast device for use in a twolamp control circuit for electric discharge lamps to shunt the auxiliary 8 comprlsinc, a transformer, a pair of main-reactors connected in circuit relation with the transformer and each disposed for connection to a separate lamp c t, a condenser and an auxiliary reactor connected in series circuit rela- -tion with only one of said main reactors, and a thermal switch having contact members conn'eeted in shunt relation with the auxiliary reactor and a heater element connected to be responsiv'e to'the current flow through the auxiliary reactor, thereby to provide for rendering said auxiliary reactor ineffective within a predetermined time after the parallel circuit in which it is connected is initially energized. 

